No. Variety matters, and it’s especially important to get variety in vegetables.

Kids can be balky eaters, but, ideally, they should learn to enjoy a wide range of foods in order to get all the nutrients they need, said Jeanne Cox, a pediatric nutritionist at Johns Hopkins Hospital in Baltimore. Feeding kids green beans every night, for instance, means they are not getting other nutrients they need. “They need broccoli, carrots, the orange and yellow vegetables in addition to the dark green,” said Cox.

The best approach, she said, is to offer small portions of a healthy protein, such as meat, fish, eggs, or poultry, along with a healthy starch like whole grain rice or even potatoes or pasta, and a vegetable and a fruit. At any given meal, the child may eat only vegetables or only starch or protein, “but in the long run, it evens out,” she said. The key is to keep presenting a variety of foods and to let kids pick from that selection.

“It takes an average of 15 tries per new food” to get a child to accept it, said Jan Hangen, a clinical nutrition specialist at Children’s Hospital in Boston.

The reason kids should “eat the rainbow,” she said, is that plants of different colors have different phytonutrients, the natural chemicals in food that are essential for health. “We know that people who eat a variety of colors tend to remain healthy,” she said, even though scientists are still working to figure out exactly what each phytonutrient does.

Frozen veggies, by the way, are fine. “Unless you’re buying food at a farm stand,” said Hangen, “the frozen vegetables are best because they are fast frozen right from the field.” The “fresh” vegetables from supermarkets often “spend a lot of time on the truck, even though they look beautiful.”